The present invention relates to electromagnetically welded, thermoplastic composite. Such a composite is particularly useful, for example, in the manufacture of window frame profiles.
Window frame profiles are typically made from wood, polyvinyl chloride, or aluminum. Although wood is rigid and aesthetically pleasing, it requires much maintenance, it is inconsistent, and has availability limitations. Polyvinyl chloride (PVC) requires little or no maintenance and is readily available and consistent, but has a low modulus and high coefficient of linear thermal expansion (CLTE). Its application in window frame profiles is therefore limited to domestic windows. Aluminum, on the other hand, has a relatively low CLTE and high modulus, but it also very thermally conductive, and requires elaborate systems to create thermal breaks to prevent significant heat loss.
In view of the deficiencies in the art, it would be desirable to discover a material that is strong and light-weight, one that has high energy absorption and high modulus, as well as low CLTE and low thermal conductivity, and one that is easy to style and shape.
The present invention addresses a need in the art by providing an article comprising a thermoplastic composite welded to a substrate, wherein either a) the composite or the substrate or both the composite and the substrate contain a dispersion of ferromagnetic particles or b) the composite and the substrate are bonded together through a ferromagnetically filled interlayer; wherein the composite is reinforced with continuous fibers.
In another aspect, the invention is a thermoplastic composite frame comprising: a) a plurality of hollow elongated thermoplastic composites having inner walls, each composite being reinforced with continuous fibers and abutting at each end to form a plane; and b) a plurality of thermoplastic joints containing a dispersion of ferromagnetic particles, wherein each joint is ferromagnetically bonded to the inner walls of abutting composite ends.
In another aspect, the invention is a method for welding a thermoplastic composite to a substrate comprising the steps of a) situating a ferromagnetically-filled thermoplastic interlayer material between the composite and the substrate; and b) subjecting the ferromagnetically-filled thermoplastic material, the thermoplastic composite, and the substrate to a radio frequency magnetic field to generate sufficient heating in the ferromagnetically-filled material to create a bond between the thermoplastic composite and the substrate, wherein the composite is reinforced with continuous fibers.
The composite of the present invention addresses a need in the art by providing a simple and effective means of preparing two- or three-dimensional thermoplastic composite profiles. Furthermore, the invention provides generally for a simple means of welding a thermoplastic composite to another thermoplastic material.
FIG. 1 is an illustration of two polyurethane engineering thermoplastic composite profiles joined together by electromagnetically welded tie layers overmolded on a thermoplastic joint.
FIG. 2 is a side view of a square outer composite profile, a ferromagnetically-filled thermoplastic tie layer, and a fitting.
FIG. 3 is a side view of a square profile of a thermoplastic overmolded composite, a ferromagnetically-filled thermoplastic tie layer, and a fitting.
FIG. 4 is an illustration of a grooved thermoplastic part welded to a polyurethane engineering thermoplastic composite part by way of a ferromagnetically-filled tie layer.